Summary: Ex. When `console.log` or similar is called, this will call
the original method, which can be quite useful.
For example, under iOS, this will log to the Safari console debugger,
which has an expandable UI for inspecting objects, etc., and is also
just useful if you are using that as a REPL.
I don't believe this incurs a meaningful performance penalty unless
the console is open, but it would be easy to stick behind a flag
if that is a problem.
Closes https://github.com/facebook/react-native/pull/2486
Reviewed By: @svcscm
Differential Revision: D2472470
Pulled By: @vjeux
dc7681e946